Sun Qian originated from Beihai Commandery. He was recommended to Liu Bei (who was then the regional inspector of Xuzhou) by the masterful scholar, Zheng Xuan. When Liu Bei was at odds with Cao Cao and he planned to flee to Yuan Shao, Sun Qian was sent as the messenger and had Liu Bei's desire granted. He and Mi Zhu were later sent to Jimeng and pleaded Liu Biao to shelter their lord. Their words convinced Liu Biao and Liu Bei was put under his care.

When Yuan Tan and Yuan Shu's brothers fought with one another, Liu Biao sent Yuan Tan a letter. A line within the letter read as, "Even brothers with no blood relation with one another, Lord Liu Bei and Sun Qian, are pained when I discuss your every argument." At least from a glance, Sun Qian was close to his lord. He, Mi Zhu, and Jian Yong were ordered to be among Liu Bei's personal staff.

As Liu Bei suppressed Yi Province, Sun Qian was promoted as the General Who Upholds Loyalty (秉忠将軍; the seat after Mi Zhu). He died of sickness soon after.

In the novel, Sun Qian was a former vassal of Tao Qian. He and Mi Zhu were recommended to Liu Bei by their ill lord and, when their master passed away, they became Liu Bei's advisers. Sun Qian told his lord to take refuge with Cao Cao when they were betrayed by Lu Bu. He continued to press for relying on the conqueror until Zheng Xuan wrote Liu Bei a letter for Yuan Shao's aid. He delivered the letter and later negotiated with Yuan Shao a second time.

Sun Qian was ordered to defend Xiaopei as Zhang Fei tried to attack Cao Cao's camp. When Liu Bei's army was scattered from their defeat, he stayed for a time with Liu Pi and Gong Du. He was caught as a spy within Cao Cao's camp and was surprised to see Guan Yu. From him, Guan Yu learned that his brother was still alive and asked Sun Qian to find Liu Bei's whereabouts. Sun Qian did so by negotiating peace with Liu Pi and Yuan Shao. While the two new parties quarreled, Liu Bei and Liu Pi awaited Guan Yu at Runan. Sun Qian reported the news to Guan Yu and he accompanied the general's journey through the five passes.

He volunteered as Liu Bei's lone negotiator to Liu Biao at Jing Province. Opposing his plea to the regional lord was Cai Mao, who Sun Qian ignored by strongly adhering for Liu Bei's virtuous nature. He acts as a secondary adviser during Liu Bei's stay with Liu Biao, suggesting to spare Cai Mao from execution and casting doubt on Xu Shu's integrity. During his master's flight at Changban, he bravely defended the eastern road to the Changjiang River. He momentarily left his lord to rejoin with Zhuge Liang's navy fleet. He participated in the Battle of Chi Bi but played a minor role as a guard and messenger. Afterwards, Sun Qian was his lord's vigilant aide during the abrupt wedding proposal staged by Sun Quan.

His last mention in the story has him rewarded for his services at Chengdu.